The invention relates to a flexible covering for power supply lines, machine tool guideways, spindles and the like, comprising a plurality of cover sections which are hinged to each other and have stops which determine on the one hand the extended position and on the other hand the minimum radius of curvature of the cover.
Telescopic steel covers are known for machine tool guideways, columns, spindles, shafts and other similar devices, wherein the individual box-like covering members are traversable in a straight line. If the telescopic steel cover is, for example, moved together with the movable part of the machine beyond the guideway, then a suitable support has to be provided to take up the weight of the cantilever telescopic steel covering. The great disadvantage of such an arrangement is to be found in the cost of the supporting structure as well as the space required by the telescopic steel cover when in its drawn-out position. On the other hand, any means of extending the guideway is likewise very expensive.
Covers (cf. the laid-open German patent application DT-OS No. 20 20 108) are also known for guideways and other parts of machine tools which consist of sections flexibly joined together, wherein the adjacent sections are connected by means of coupling bosses which engage in recesses of the adjacent member in such a manner that two extreme swivelling positions are limited (of which the one determines the extended position of the cover, and the other the minimum radius of curvature of the cover when in the curved state.) Such a self-supporting cover avoids the disadvantages of the previously described construction, as a special support structure for the part of the cover projecting beyond the guideway is not required and the space required for the cantilever part of the cover can be considerably reduced. However, the fabrication of the individual sections of such a cover with their axially symmetrical coupling bosses and coupling recesses involves considerable expense, and the sides of the guideway are not covered by this arrangement.
Moreover, movable covers are also known (in the form of self-supporting power supply chains, cf. German utility model No. 66 00 307) for accommodating power supply lines, wherein chain links which are hinged together come into engagement in pairs and have trapezoidal front edges, thereby limiting the extended position, on the one hand, and the minimum radius of curvature of the cover, on the other. Cover arrangements of this kind are so rigid that they can be walked on by the operating personnel. The known construction, however, have the disadvantage that the opening and closing gap between co-operating stop edges presents an exceptionally great danger of accidents occurring when the cover arrangement is moved.
This accident hazard is avoided by another known cover for power supply lines (cf. German patent specification No. 15 74 369) wherein the individual cover sections that are hinged together are largely sealed off from the outside. For this purpose, resilient cover plates are provided on the upper side (or outside) and the lower side (or interior) of the cover, which are capable of flexible distortion in the curvature zones of the cover and which are thus constantly in contact with each other, irrespective of the angle between adjacent cover sections. The disadvantage of this arrangement is that the necessity of designing the cover plates to be flexible and resilient excludes any construction which attains a high degree of rigidity. In particular the cover plates cannot be designed to be so flexibly resilient, on the one hand, that they remain in contact in all swivel positions, and yet sufficiently rigid, on the other hand, for the cover arrangement to be walked on without difficulty when of large overall width.